In this study, we evaluated the property change and relationship between hematological and biochemical parameters in exposure group and control group by multiple inhalation exposure, of NO2. In case of leukocyte, change of hematological property increased significantly in statistics (p<0.05) in mice experiment. in case of hematocrit of exposure group, it was of decreased significantly in statistics. the tendency of hemoglobin and hematocrit was similar to all for three case. in case of methmoglobin that of the exposure group in mice experiment was meaning increased(p<0.05). For the NO2 influence in biochemical property, total protein and triglyceride was decreased but not significant in statistics, albumin was decreased in the exposure group in the animal experiments. blood urea nitrogen and creatinine increased significantly in statistics in the animal experiments. uric acid and lactate dehydrogenase in serum increased significantly in the exposure group. We have to evaluate risk assessment for the NO2 of indoor air pollutant in low concentration and long time.